MM Pricing procedure?

Dear Gurus,

clients wants to implement one new condition type "exmn" to sto pricing proc "xm1000".their requirement is as below:

Additional condition is required to implement minimum excise tax calculation:

"exmn" - Excise Tax Minimum

Condition exmn should not be mandatory as the same pricing procedures are being used for Lithuania, Latvia and Estonia, but minimum excise tax calculation rule is not applicable for Lithuania.

System should check, if minimum excise tax is required (if it was defined).

If the result of the standart excise tax calculation is lower than minimum excise tax rate, then "exmn" is applicable for the product and condition "exmn" will be used.

I have done the configuration, but manually i m entering the value..

as per the above requirement, it should come automatically.

kindly guide me...

thnks in advance for help..